Wednesday, June 18, 2008

Diet and Eating Habits.A. Food preferences and resources.1. Polar bears feed mainly on ringed seals and bearded seals. Depending upon their location, they also eat harp and hooded seals and scavenge on carcasses of beluga whales, walruses, narwhals, and bowhead whales.

2. Aquatic stalk.a. The aquatic stalk is a method also used in summer when seals haul out on sea ice.b. The polar bear swims toward a hauled-out seal. Once the polar bear reaches the ice edge, the bear quickly emerges from the water and grabs the seal with its claws or teeth.3. Stalking birth lairs.a. Stalking ringed seals at their birth lairs is a hunting method polar bears use in spring, when ringed seals give birth to their pups.b. Ringed seal birth lairs are caves built under snow drifts next to a hole in the ice. The snow drifts are on stable sea ice attached to land.c. Once a polar bear identifies a birth lair, it slowly and quietly positions itself next to the lair. If a polar bear smells or hears a seal in the lair, it slowly raises up on its hind legs and crashes down with its front paws to break through the lair roof.d. To break the roof's hard surface, several tries are sometimes needed, which may allow the seal to escape into the water.e. This method is most commonly used by polar bear females with cubs under one year old.(1) Mother seals and pups have the high fat content needed for hungry polar bear mothers and their growing cubs.(2) Male polar bears that may attack young polar bear cubs don't normally hunt seals in birth lairs.(3) Birth lairs are usually on sea ice attached to land, allowing young cubs (who have little protective blubber) to avoid crossing water.

4. Eating.a. Once a seal is captured, a polar bear bites it several times on the head and neck before dragging it several meters from the water to feed.b. The skin and fat are eaten first, followed by the meat.c. Polar bears often stop to wash during feeding, using water nearby or rubbing in the snow.d. Polar bears don't always eat the entire kill. Carcass remains are scavenged by other bears, arctic foxes, and gulls.